JPS58206919A - Rotation detecting device - Google Patents

Abstract

PURPOSE:To make a titled device small-sized by simplifying its structure and to reduce its cost, by unifying a rotating speed detecting system and a rotating phase detecting system so that both of them can be detected by one rotation detecting system. CONSTITUTION:A disk 2 is stuck to a revolving shaft 1 of a motor, and a ring magnet 3 is fitted into its circumferential edge. Plural S and N magnetized parts 4 for detecting a rotation are formed at equal intervals on its outside circumferential face. A rotating speed detecting signal having frequency modulated by a rotating speed is obtained by detecting said magnetized part by a detecting element 5 of a magnetic head, DME, a Hall element, etc. A nonmagnetized part 6 for detecting the rotating phase is formed extending over longer width than one pitch of the magnetized part 4 on one part of the circumferential face of the ring magnet 3. A square wave signal obtained by shaping at a threshold level is applied to a phase detecting circuit, in which a difference of pulse width of the speed detecting part and the phase detecting part is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation detection device for obtaining a rotation speed detection signal and a rotation phase detection signal.

In a conventional rotation detection device of this type, a rotation speed detection system and a rotation phase detection section are separately provided on a rotating body (for example, a disk attached to a rotating shaft of a motor), and each is provided with a separate detection means. Detected. As the rotational speed detection section, for example, magnetic sections arranged at equal pitches around the circumference of the magnetic disk are used, and by detecting this with a magnetic head, a Dfshi IE1 Hall element, etc., the rotational speed can be determined. Detection signal is obtained. Further, as the rotational phase detection section, for example, at least one magnet piece provided on the peripheral edge of the rotating disk is used, and this is detected by the above-mentioned magnetic conversion element to obtain a rotational phase detection signal. In addition, there are optical detection systems that use a slit formed in a rotating body and a pair of light-emitting and light-receiving confections, and electrostatic or magnetoresistive type systems that have gear-shaped rotating/fixed opposing electrodes or pole pieces. Detection systems are also known.

The present invention combines the rotational speed detection system and the rotational phase detection system as described above so that both can be detected by a single rotational detection system, and the structure is simplified to achieve miniaturization and cost reduction. It is a decoy.

Examples of the present invention will be described below. FIG. 1 is a plan view of the rotating side of a rotation detecting device showing one practical example of the present invention.
2) was seen once, and around that time there was a ring mug, tot.
3+ is inserted. FIG. 2 is a partially enlarged plan view showing the details of the bottom part of FIG.
An N@magnetic portion (4) is formed. By detecting this magnetized portion with a detection element (5) such as a magnetic head, DME, or Hall element, a rotation detection signal having a frequency modulated by the rotation speed is obtained.

As shown in Fig. 2, a non-magnetized part (6) for detecting the rotational phase is formed in one part of the surface of the ring magnet (3) over a width longer than one pitch of the magnetized part (4). Note that this non-magnetized portion (6) may be a notch, or this notch may be filled with a non-magnetic material (for example, synthetic resin) different from that of the ring magnet (3). It's okay.

FIG. 6 is a block diagram of a motor control circuit using the rotation detection device of the present invention, and FIG. 4 is a waveform diagram for explaining its operation. A rotation detection device shown in FIGS. 1 and 2 is attached to the motor (8), and a detection signal FG shown in FIG. 4A is obtained from the detection element (5). This detection signal F
G is the ring magnet do (N@ part of 3I (41 is the sine wave method), and the non-magnetized part (6) is substantially over one period or more of the detection signal of the magnetized part as shown in Figure 4. This results in an irregular pulse train in which a proper detection signal cannot be obtained.

The detection signal FG is given to the waveform shaping circuit (9+,
As shown in Figure B, the signal is shaped into a rectangular wave at a predetermined threshold level. The rectangular wave signal obtained by shaping is given to the phase detection circuit (101), where the difference in pulse width between the speed detection section and the phase detection section is discriminated, and the pulse width is determined as shown in Fig. 4C. One phase detection signal PG corresponding to a wide portion is extracted per rotation.

The phase detection signal PG is applied to a phase comparison circuit aυ made up of, for example, a PLL, and is compared there with a reference phase. The phase error output of the comparison result is used as a speed error signal in the adder circuit (12+), and then given to the motor drive/starter circuit (13), and the output is used to control the motor (8).
) is controlled.

On the other hand, the rectangular wave signal (No. 417B) output from the waveform shaping circuit (9;
Non-magnetized part (6) for phase detection that is applied to and seen by rllv
is controlled.

On the other hand, the rectangular wave signal (FIG. 4B) output from the waveform shaping circuit (9) is transmitted to the speed measurement section detection circuit Q4 for speed servo.
1, the speed detection pulse F shown in the fourth diagram excluding the pulse portion corresponding to the non-magnetized portion (6) for phase detection
G' is extracted. At this time, the phase detection signal PG is FG'
Used as a reference signal for extraction. Note that since the waveform of the detection signal Ii'G in the vicinity (front and rear) of the non-magnetized portion (6) is easily disturbed by non-magnetization, the speed detection pulse FG' in this vicinity may be excluded.

The extracted speed detection pulse FG' is sent to the speed comparison circuit u5)
The frequency of the speed detection pulse is converted into an error voltage (speed servo voltage) with respect to the speed reference. The frequency (f) -M pressure-close conversion method may be a conventionally known method, for example, speed detection is pulsed and fV conversion is performed. The reduced screw pressure is compared with a reference level (speed reference amount) to form a speed servo pressure.

The speed servo voltage is added to the phase error rolling voltage by an adder circuit +13+ and then applied to the motor drive/starter circuit 0:(1), and the speed of the motor (8) is kept constant based on its output l.

In the sample and hold circuit of the f-V converter in the speed comparison circuit (151), the data processing shown in the fourth diagram is performed. That is, the data processing shown in the fourth diagram is applied to the motor (8) according to the time pitch S1 between a and b in the fourth diagram. The power driving current i is determined,
il is held by the temporal pitch H1 between b and c that comes next. At the same time, the pitch S2 between b and c determines the displacement flow 12 to be applied to the motor next.

Since one cycle cannot be recorded between c and d for normal speed detection, the following processing is performed. The drive flow 12 determined by the toe pitch 82 should be held until the next edge d, but
$4 Use the phase detection signal PG in Figure C to perform logical processing that ignores the edge of d, and hold 12 until the edge of e0.Furthermore, using the above phase calculation 1d'gj PG m physics, d-e The current i3 of the driver 1117J is determined with the same pitch S3 and held during the period 1-13 of e-f.

Such processing eliminates the influence of the non-magnetized portion (6) on the speed servo signal. This makes it possible to perform both phase servo and speed servo using the output of one detection element (5).

In Fig. 3, the output from the waveform shaping circuit (9+) and the phase detection circuit is also given to the motor drive position detection circuit αb, and the phase detection signal PG in Fig. 4C is used as a reference (reset signal).
The rectangular wave signal of FIG. 4B is frequency-divided by a predetermined ratio.

If the motor (8) is, for example, a three-phase brushless motor,
By the frequency division described above, a switching signal for the S-phase coil is formed. This switching signal is sent to the motor drive/starter circuit (+31), where it is sent to the adder circuit +121.
6 according to the output (speed servo voltage and ten phase servo voltage)
A phase switching No. 16 is formed, which drives the motor (8). Note that this circuit includes a starter circuit that ignores the speed servo voltage and phase servo voltage and applies the power supply voltage to the motor 18 during motor rotation.Next, Figure #I5 is the phase detection circuit of Figure 3. Circuit (1 (11) and a specific circuit diagram of the speed measurement section detection circuit I,
is a waveform diagram showing the operation. .

As shown in FIG.
given to. This mono-multicircuit a-toge is a retriggerable source multivibrator (one-shot 0, which is triggered by the rising edge of the four inputs and reset by the falling edge of the reset input.Therefore, the mono multi circuit 0
1, a metastable output with a period Illo in the frequency detection part of No. 1 and a pulse width T only in the phase detection part is obtained as shown in FIG. 6B'.This metastable output and the input rectangle [signal is nandogeni') (l
The phase detection signal PG shown in FIG. 4 and FIG. 0ζ is obtained.

The rising edge of this phase detection signal PG is the subject of comparison in the phase servo system. Note that the entrance edge of the phase detection portion may be detected by a method similar to Pr1 and used as the phase detection signal.

The rectangular wave signal in FIG. 6B is generated by the speed measurement section detection circuit (14
The phase detection signal PG of the output of the counter 09 is also applied to the clear input OL of the counter 1.

The counter koji is reset when the PG scratch signal rises, and the edges of the square wave signal are changed to 0.1, 2°3, . . . as shown in Fig. 6B.
・・・・・・・・・ Count. The counting output is given to the ROM (21) as an address signal, and the oROM (2υ-ζ is a ring magnet (3: speed detection wear A table is prepared in advance so that the required output can be obtained corresponding to the number of magnetized poles of the magnetic part (4), and the output is shown in the 6th EDJC.
, in the interval 4 to 5-..., ゛ is low level-
The level is high in the section 11~2.3~4.5~6... ◎Also, the non-magnetized part for phase detection (6
In the section n-1 (n4 is the number of magnetized poles) corresponding to the detection part of J, the level is 1. In order to achieve this, a high-level pulse (
A pulse corresponding to the 6th El) and the counting interval 0 to 3 is formed. Furthermore, due to the influence of the non-magnetized portion (6), the detection signal is generated between b and c and between d and e in the fourth diagram. # If the accuracy is not good ζ this will cover these areas! Signal (n-
2 to 3), and the immediately preceding speed detection information may be held in this section.

Next, FIG. 7 shows another embodiment of the rotation side of the rotation detection device of the present invention. This example is a brushless motor ■-
A ring-shaped field magnet) CLA is used, and this magnet is fixed to the single rotation shaft (11) via the rotor yoke (C). The area of 4I# is used as an example of 4 poles to form the motor field. The motor coil is in this layer 4I1
and the rotation axis of the motor (!1).

Outside the area 041, a ring-shaped non-magnetized area (a magnetized area (c) for rotation detection is formed with 29 in between. This magnetized area (c) is for speed detection like the 1N) It consists of a magnetized part (4) and a non-magnetized part (6) (or non-magnetic part) for phase detection.A detection element (5) is located close to this magnetized region (c) for rotation detection. ), velocity and phase detection is performed.

Although the preferred embodiments of the present invention have been described above,
Various modifications can be made based on the technical idea of the present invention. For example, a plurality of fine slits for speed detection may be formed on the rotation side, and optical detection may be performed using a pair of light emitting and light receiving elements.

The phase signal can be detected by widening a part of the slit and separately separating the detected pulse in this part based on the difference in pulse width from other pulse widths.

As described above, in the present invention, a frequency detection part for speed detection and a phase detection part for co-rotation phase detection are formed on the rotational locus of the rotating part facing T to one detection block.

Therefore, according to the present invention, the structure of the speed and phase detection system can be simplified, and it is possible to achieve compactness and reduce manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the rotation side portion of a rotation detection device showing an embodiment of the present invention, FIG. 2 is an enlarged plan view of the main part of FIG. 1, and FIG. 4 is a waveform diagram for explaining the operation of FIG. 3, and FIG. 5 is a circuit diagram showing an example of the phase detection circuit and speed measurement section detection circuit of FIG. 3. 5 is a diagram illustrating waveform factors for the operation shown in FIG. 5, and FIG. 7 is a plan view of a rotor of a motor showing another embodiment of the rotation detecting device of the present invention. In addition, in the symbols used in the drawings, (11......Rotary shelf (2)
・・・・・・・・・・・・・・・Disc (3)・・・・
・・・・・・・・・・・・Ring magnet (4)・・・
・・・・・・・・・・・・Magnetized part (6)・・・・・・
......Detection thread (6)...
・・・・・・Non-magnetized part (8)・・・・・・・・・・・・
...It is a motor. Agent Ueya Yoshio Tsuneko Toshiki Sugiura E'
-Figure 7 2 Continued from page 1 0 Inventor Tsutomu Kajiwara Sony Corporation Technical Research Center, 1-7-4 Konan, Minato-ku, Tokyo

Claims (1)

[Claims] It consists of a rotating part, a stationary side detection means, and a force sensor, and a frequency detection part subdivided into a plurality of parts for detecting rotational speed, and at least one phase detection part for detecting rotational phase are each said detection means. A rotation detection device characterized in that the rotation detection devices are arranged on the same rotation locus of the opposing rotating parts.